1. Technical Field
The present invention relates to a technology for a head mounted display.
2. Related Art
A head mounted display (HMD), which is a display apparatus mounted on a head, has been known. A head mounted display generates image light, for example, by using a liquid crystal display and a light source and guides the generated image light to a user's eyes by using a projection system and a light guide plate to allow the user to visually recognize a virtual image. The head mounted display is classified into two types: a transmissive head mounted display that allows the user to visually recognize an outside scene as well as a virtual image; and a non-transmissive head mounted display that does not allow the user to visually recognize an outside scene. A transmissive head mounted display is further classified into an optically transmissive head mounted display and a video-transmissive head mounted display.
JP-A-2014-71230 discloses a display apparatus that acquires information on the luster of a user's eyes imaged with an imager, sets an area around the user's focal position where a virtual image is displayed based on the acquired information on the luster, and lowers the luminance and contrast in the area outside the set area. JP-A-2013-257492 discloses a display apparatus that adjusts, based on the luminance in a non-display area where no image is displayed, the luminance in an image display area where an image is displayed. JP-A-2013-254358 discloses an image processing apparatus that identifies the center of the range of a user's sight line based on the orientation and motion of the user's pupils detected with a camera and adjusts the contrast in a portion of a displayed image that corresponds to the identified center of the range of the sight line.
The technologies described in JP-A-2014-71230, JP-A-2013-257492, and JP-A-2013-254358, however, simply change the luminance and contrast in a predetermined area in accordance with the direction of a user's sight line, and there has been a desire to change other factors as well as the luminance and contrast in accordance, for example, with the direction of the user's sight line. Additionally, in image processing technologies of related art, size reduction, cost reduction, resource conservation, ease of manufacturing, improvement in ease of use, and other improvements have been desired.